This invention generally relates to ultrasonic pulse echo imaging, and more specifically, to ultrasonic pulse echo imaging based on the distortion of ultrasonic signals transmitted into samples.
Ultrasonic pulse echo imaging is widely used in many medical applications. While this technique has received wide acceptance, it would be desirable to improve the resolution of the images formed from this technique. For example, ultrasonic pulse echo imaging in inhomogeneous media suffers from significant lateral and contrast resolution losses due to the defocusing effects of the inhomogeneities of the media. The losses in lateral and contrast resolution are associated with increases in the width of the main beams and increases in side lobe levels, respectively.
These two forms of resolution loss represent a significant hurdle to improving the clinical utility of biomedical ultrasonic imaging. A number of research efforts are currently underway to investigate the defocusing effects of tissue and to consider corrective measures. These efforts, however, generally assume linear propagation and base the image-formation process on the reception of the transmitted pulse.